Hi Nigel
Just create a new delphi project and add an imageenvect component and one button to the form.
In the formcreate event add the following code:
  ImageEnVect1.IO.LoadFromFile('<your picture>');
  ImageEnVect1.MouseInteractVt := [miPutLineLabel];
  ImageEnVect1.ObjEndShape[-1] := iesOutArrow;
  ImageEnVect1.ObjBrushStyle[-1] := bsSolid;
and in the button click event:
  ImageEnVect1.CopyObjectsToBack(True);
  ImageEnVect1.SelAllObjects;
  while ImageEnVect1.SelObjectsCount > 0 do
    ImageEnVect1.RemoveObject(ImageEnVect1.selobjects[0]);
Start the project, draw some arrows and click the button. 
Regards
David